Assessment Questions Key
1) List two pre-conditions that must be met for • Crop selection
seed germination and four environmental
conditions that must be achieved for optimal • Ability to intensively manage large numbers
seed germination. of plants in a small area
Pre-conditions: • Efficient use of seed, water and space
• Viable seed Disadvantages of transplants:
• Dormancy factor released • Additional infrastructure costs
Necessary environmental conditions for seed • Additional skill and labor required
germination and role of each:
• Not all crops grow or transplant well from
• Optimal temperature range: To increase the containers
rate of respiration
• Additional non-renewable resource use
• Optimal moisture range: To soften seed coat
and increase the rate of respiration • Often results in more total days of growth
• Aeration: To provide adequate air circulation 4) Why is the careful selection of crop varieties
for supplying oxygen used in respiration important?
and remove carbon dioxide produced during
respiration • To help assure disease resistance
• Light: Though not needed for germination • To help assure good crop performance in
of all seeds, light stimulates increased different climates or micro-climates
respiration in some plants
• To help assure other crop qualities such as
2) What is the optimal average daytime storage, visual aesthetics, flavor, etc.
temperature range that should be maintained
in the greenhouse for the germination and 5) What are four important qualities of a
early growth of most annual vegetables and propagation mix? List two propagation mix
cut flowers? What would be the minimum constituents that may be used to assure each
nighttime temperature? of the previously listed qualities.
• Optimal average temperature range is • Drainage. Constituents that impart this
between 65–85ºF. (The average optimal quality: Perlite, sand, soil, leaf mould,
germination temperature for most vegetables gravels and lava rock, and to a lesser extent,
and cut flowers is 82ºF. Please see appendix vermiculite, compost, peat moss, and coir
2 for specific minimum, maximum, and fiber
optimal germination temperatures.)
• Aeration. Constituents that impart this
• Minimum nighttime temperature should not quality: Perlite, sand, soil, leaf mould,
dip below 55ºF gravels and lava rock, and to a lesser extent,
vermiculite compost, peat moss and coir fiber
3) List four advantages of the use of
greenhouse-raised transplants over direct • Density. Constituents that impart this quality:
seeding of crop plants. Describe two Sand, soil, gravel, compost, and leaf mould
disadvantages.
• Nutrient availability. Constituents that
Advantages of transplants: impart this quality: Compost, soil, mineral
and organic matter amendments, and leaf
• Season extension mould
• Ability to manage environmental conditions: • Water-holding capacity. Constituents that
Temperature, moisture, air circulation and impart this quality: Compost, peat moss and
growing media coir fiber, vermiculite
Assessment Questions Key Unit 1.3 | Part 1 – 137
Propagation/Greenhouse Management
6) What pieces of information are commonly • The use of disease-free seed stock
documented in the propagation process and
why? • Management of environmental conditions
of greenhouse (air circulation, temperature,
• Genus and species of crop light) and propagation media (moisture,
• Variety of crop aeration, nutrients) within the optimal range.
• Date sown Good cultural practices.
• Date pricked out (if applicable)
• Seed company name • Monitoring
• Seed lot (year seed was produced for)
Why: The above would provide adequate Active measures:
information for future trouble shooting and • Roguing affected crops
the selection of crops during variety trials
• Biological control
7) What is the “hardening off” process?
The gradual exposure and acclimation • The use of acceptable chemical controls
of greenhouse-raised transplants to the
environmental conditions of the field.
8) List two characteristics of cell-tray-grown
seedlings at transplanting maturity.
• Second set of true leaves initiated
• Root knit
9) List two necessary steps for preparing
seedlings before transplanting them to the
field or garden.
• Pre-moistened to 75% field capacity
• Hardened-off for 3–21 days
10) List the environmental conditions most
favorable for the successful bare-root
transplanting/ pricking out seedlings grown
in a flat format.
• Low light levels
• Low temperatures
• Low wind velocity
11) Describe four preventive measures and two
active measures used to control fungal plant
pathogens in greenhouse facilities.
Preventive measures:
• Proper sanitation of propagation media,
facilities, and containers
• The selection and use of disease-resistant
varieties
• The selection and use of climate-appropriate
varieties
Part 1 – 138 | Unit 1.3 Assessment Questions Key
Propagation/Greenhouse Management
Resources
PRINT RESOURCES requirements by seeds, cuttings, grafting and
budding, and tissue culture are discussed in
*Books that are particularly useful, best places to detail.
spend your money.
*Dreistadt, Steve, and Mary Louise Flint. 2001.
*Beytes, Chris (ed.). 2011. Ball RedBook, Volume 1: Integrated Pest Management for Floriculture and
Greenhouses and Equipment, 18th Edition. Greens- Nurseries. Publication 3402. Oakland, CA: Uni-
boro Books. versity of California Division of Agriculture and
Natural Resources.
Covers all aspects of greenhouse equipment—
the structures themselves, benches, irrigation, Outstanding resource for developing a pest
curtains, environmental controls, machination, management program.
and the greenhouse as a retail facility. The most
recent developments in greenhouse evolution Flint, Mary Louise. 1998. Pests of the Garden and
are discussed, as are the varieties of available Small Farm and Garden: A Grower’s Guide to Using
greenhouse structures, from freestanding Less Pesticide, Second Edition. Publication 3332.
and gutter-connected greenhouses to shade Oakland, CA: Universitiy of California Division of
houses and open-roof greenhouses. Includes Agriculture and Natural Resources.
information on how to market products and
how to operate a retail store from a greenhouse. Excellent tool for the identification of common
greenhouse pests and pathogens.
Cranshaw, Whitney. 2004. Garden Insects of North
America: The Ultimate Guide to Backyard Bugs. Flint, Mary Louise, and Steve Dreistadt. 1998. Nat-
Princeton, NJ: Princeton University Press. ural Enemies Handbook: The Illustrated Guide to
Biological Pest Control. Publication 3386. Oakland,
A comprehensive, user-friendly guide to the CA: Universitiy of California Division of Agriculture
common insects and mites affecting yard and and Natural Resources.
garden plants. Uses full-color photos and
concise, clear, scientifically accurate text, to A valuable resource for biological control of
describe the vast majority of species associated pests and pathogens.
with shade trees and shrubs, turfgrass, flowers
and ornamental plants, vegetables, and fruits. Greer, Lane. 2005. Plug and Transplant Production
For particularly abundant bugs adept at for Organic Systems. ATTRA, National Center for
damaging garden plants, management tips are Alternative Technology (NCAT). www.attra.ncat.org/
also included. Provides basic information on attra-pub/PDF/plugs.pdf.
host plants, characteristic damage caused to
plants, distribution, life history, habits, and, Describes the process of producing transplants
where necessary, how to keep “pests” in check. using methods that conform to National
Organic Program (NOP) regulations. Includes
Deno, Norman. 1994. Seed Germination Theory information on containers, media, equipment,
and Practice, 2nd Printing. Self published, State Col- nutrition, irrigation, pest management, and
lege, PA. naldc.nal.usda.gov/download/41278/PDF more.
Important reference on principles of seed Hanan, Joe. 1998. Greenhouses: Advanced Technol-
germination and the use of specific techniques ogy for Protected Horticulture. Boston, MA: CRC
for a wide array of cultivated crops. Press.
Dirr, Michael A., and Charles W. Heuser, Jr. 2006. Exhaustive reference on all aspects of
The Reference Manual of Woody Plant Propaga- greenhouse design and management, written
tion: Seed to Tissue Culture, 2nd Edition. Cary, NC: principally from a conventional perspective, but
Varsity Press, Inc. with much valuable information for the organic
grower.
Over 1,100 species and their propagation
Resources Unit 1.3 | Part 1 – 139
Propagation/Greenhouse Management
Hartmann, Hudson, Dale Kester, Fred Davies, *Styer, Roger, and David Koranski. 1997. Plug and
Jr., and Robert Geneve. 2010. Plant Propagation: Transplant Production. Batavia, IL: Ball Publishing.
Principles and Practices, 8th Edition. Upper Saddle
River, NJ: Prentice Hall. Excellent discussion on soils and containers
and detailed information on managing
The standard reference tool for propagators, environmental conditions for vegetable and cut
covering all aspects of sexual and asexual flower transplants.
propagation, principally from a large-scale,
conventional focus. Thompson, Peter. 2005. Creative Propagation, 2nd
edition. Portland: Timber Press.
Johnston, Robert Jr. 1983. Growing Garden Seeds:
A Manual for Gardeners and Small Farmers. Albion, Very user-friendly guide to growing plants from
ME: Johnny’s Selected Seeds. seed, cuttings, and divisions.
Brief but valuable reference on seed viability Walls, Ian. 1996. The Complete Book of the Green-
and seed production strategies. house. London: Ward Lock.
Jozwik, Francis X. 2000. The Greenhouse and Geared toward small-scale and backyard
Nursery Handbook: A Complete Guide to Grow- growers, this book provides good information
ing and Selling Ornamental Container Plants. Mills, on greenhouse design and management tools.
WY: Andmar.
WEB-BASED RESOURCES
Good general information for small- to
medium-scale growers. Appropriate Technology Transfer for Rural Areas
Maynard, Donald N., George J. Hochmuth, and www.attra.org
James Edward Knott. 2007. Knott’s Handbook for
Vegetable Growers, 5th edition. Hoboken, NJ: John ATTRA provides excellent information on
Wiley & Sons, Inc. numerous topics. For Propagation, see especially
titles from the Greenhouse Production of the
The standard reference for field-scale Master List of Publications for topics such as
vegetable production, but also provides many soil mixes for containers, plug and transplant
valuable charts on seed viability, germination production, amendments, supplemental
temperatures, days to germination, etc. fertilizers, compost tea and much more.
Milne, Lorus Johnson, and Margery Milne. 1980. Biology Resources DG Mackean
National Audubon Society Field Guide to North
American Insects and Spiders. New York: Alfred A. www.biology-resources.com
Knopf.
An excellent website with links to illustrations
Great visual reference for identifying both of bean, pea, sunflower, and wheat seed
beneficial and pest species. structure and germination; time lapse videos
of mung beans, corn and peas germinating;
Olkowski, William, Sheila Daar, and Helga Olkows- digestable Powerpoint presentations on
ki. 1991. Common Sense Pest Control. Newtown photosynthesis, cell division, and respiration.
CT: Taunton Press.
Cornell Resource Guide for Organic Insect and Dis-
Excellent reference for non-toxic pest control ease Management
strategies geared both for homeowners and
production-oriented growers. web.pppmb.cals.cornell.edu/resourceguide/
Rubatzky, Vincent E., and Mas Yamaguchi. 1999. Thorough guide to pest and disease
World Vegetables: Principles, Production, and identification in vegetable crops, primarily for
Nutritive Values, 2nd edition. Gaithersburg, MD: in-the-ground issues, but can be applied to
Aspen. seedlings as well. Useful content on organic
materials/inputs for pest and disease control,
Invaluable resource on the history and origins of most of which have direct application in the
major world vegetable crops and their cultural greenhouse.
requirements.
Part 1 – 140 | Unit 1.3 Resources
Propagation/Greenhouse Management
eXtension, Organic Potting Mixes extension.umass.edu/floriculture/fact-sheets/
organic-greenhouse-production-and-resources
www.extension.org/pages/20982/organic-pot- Provides information and links to a wide array
ting-mix-basics#.VN0ZB7DF_v6 of topics germane to organic growers, including
biocontrol, growing media and fertility inputs.
Covers basic information about organic potting
mixes for organic farming systems. extension.umass.edu/floriculture/greenhouse-
best-management-practices-bmp-manual
Integrated Pest Management, UC Davis Provides link to lengthy publication on Best
Management Practices for greenhouses. Focus is
www.ipm.ucdavis.edu on conventional production, but contains lots of
information relevant to organic production.
Excellent resource for insect identification and
non-chemical control strategies, as well as SEED COMPANIES
links to other sites concerned with pests and
pathogens. While focused on California, the The following sources offer exclusively GMO-free
content is highly transferable to growers in varieties, specify if their seed is fungicide treated,
other regions. and can supply letters for your Certifier stating that
your purchases are in compliance with the USDA’s
New York State/Cornell IPM Program National Organic Program (NOP) regulations.
www.nysipm.cornell.edu Baker Creek Heirloom Seeds
www.rareseeds.com
Valuable resource covering many fruit and Large collection of heirloom and difficult-to-find
vegetable crops, including identification vegetable seeds.
information, cultural practices and inputs to
manage pests and diseases. Botanical Interests
botanicalinterests.com
Royal Horticultural Society Purveyor of vegetable, flower, and herb seeds,
many organic and heirloom varieties.
www.rhs.org.uk/Advice/Profile?PID=710
Bountiful Gardens
Provides clear definition of F1 Hybrids and www.bountifulgardens.org
explanation of how F1 Hybrids are produced, as Vegetable and small grain seeds, seeds for
contrasted with open pollinated seed varieties. compost biomass production, principally open-
pollinated varieties, nutritionally dense crops.
www.rhs.org.uk/advice/profile?PID=501
Fedco
Provides straightforward explanation of www.fedcoseeds.com
methods and conditions for growing seedlings Vegetable, flower, and herb seeds, tubers and
indoors. allium bulbs, many organic and open pollinated
varieties.
Soil Foodweb
Fred C. Gloeckner Co.
www.soilfoodweb.com www.fredgloeckner.com
Flower seeds, bulbs, plug broker, and grower
A clearinghouse for information and research supplies.
summaries on soil ecosystem process and a
product, services and resource for how to grow Geo Seed
crop plants without the use of pesticides or www.geoseed.com
inorganic fertilizers. Includes how-to manuals Flower, ornamental grass, and perennial seeds
on the production of compost teas. for cut flower growers.
University of Massachusetts Extension Greenhouse
Crops and Floriculture Program
extension.umass.edu/floriculture/fact-sheets/
greenhouse-management-engineering
Links to many valuable website pages for
organic and conventional greenhouse producers
on design, energy efficiency, water management,
environmental management, pest and disease
monitoring, and more.
Resources Unit 1.3 | Part 1 – 141
Propagation/Greenhouse Management
Germania Seed Johnny’s Selected Seeds
www.germaniaseed.com www.johnnyseeds.com
Flower seeds, select vegetables, plug broker Vegetable, herb, and flower seed, production
representing many annual and perennial plug supplies, numerous organic varieties and a range
producers. of seed pack-out sizing.
Gourmet Seed International Kitazawa Seed Co.
www.gourmetseed.com www.kitazawaseed.com
Focusing on vegetable and herb seeds of unusual Packet and bulk vendor of vegetable seeds,
varieties, many heirlooms. featuring many Asian varieties not readily
available from other sources.
Harris Seeds
www.harrisseeds.com Modena Seed Co.
Vegetable and flower seeds, good line of organic www.modenaseed.com
varieties, plug broker, catering to both home Extensive cut flower seed selection, great pricing
gardeners and professional growers. and volume sizing.
Hearne Seeds Native Seed SEARCH
hearneseed.com www.nativeseeds.org
Full line of cover crop seeds, both conventional Vegetable and non-cereal grain seeds, land race
and organic. peppers, with core mission to preserve and
distribute the traditional crops of the native
High Mowing Seed Co. peoples of the Southwestern U.S.
www.highmowingseeds.com
Offers over 600 varieties of heirloom, open Ornamental Edibles
pollinated, and hybrid seeds, 100% organic www.ornamentaledibles.com
collection of vegetable, herb, and some flower Large collection of salad and braising greens,
seed. along with many other vegetables.
Horizon Herbs Osborne Seed Co.
www.horizonherbs.com www.osborneseed.com
Extensive collection of medicinal and culinary Good selection of vegetables and herb seeds for
herbs and other useful plants from around the the professional grower.
world.
Redwood City Seed Co.
Ivy Garth Seed Co. www.ecoseeds.com
www.ivygarth.com Eclectic collection of heirloom and open
Flower and vegetable seed featuring the latest pollinated varieties and huge selection of hot
varieties, and a broker for many plug growers. peppers.
J. L. Hudson Seedsman Renee’s Garden Seeds
www.jlhudsonseeds.net www.reneesgarden.com
A “public access seed bank,” focused on the Vegetable, herb, and flower seeds, great diversity
preservation of botanical diversity and the geared principally toward gardeners.
distribution of rare plants from every continent;
species span the scope of ethnobotanical Richter’s Herbs
interests. www.richters.com
Extensive line of culinary and medicinal herb
seeds; many varieties sold as young plants.
Part 1 – 142 | Unit 1.3 Resources
Propagation/Greenhouse Management
Seed Savers Exchange PLUG/SEEDLING GROWERS AND BROKERS
www.seedsavers.org
Heirloom vegetable and flower seed, some Fred C. Gloeckner Co.
bulk packaging and some organic offerings, www.fredgloeckner.com
commercial sales are an extension of non-profit Broker
network of membership organization.
Germania Seed Co.
Seeds from Italy/Franchi www.germaniaseed.com
www.growitalian.com Broker
Many hard-to-find European vegetable varieties,
and an extensive collection of chicories, Gro’n Sell
untreated and mostly open pollinated offerings. www.gro-n-sell.com
Grower of huge collection of annuals and
Siskiyou Seeds perennials for cut flower and bedding plant
www.siskiyouseeds.com production.
100% organic seeds, offering vegetables, grains,
flowers, and herbs. All seed sources listed in Growers Transplanting, Inc.
catalogue. growerstrans.com
Vegetable transplant producer geared toward
Snow Seed Co. larger-scale producers.
snowseedcompany.com
Large selection of vegetable seeds, with many Harris Seed Co.
organic offerings, sold in bulk quantities for www.harrisseeds.com
larger-scale production. Broker
Southern Exposure Seed Exchange Headstart Nursery
www.southernexposure.com www.headstartnursery.com
Vegetable, herb, and flower seeds, geared Producer of vegetable and ornamental
especially for Atlantic seaboard growing transplants for mid-scale and larger growers.
conditions, seed saving supplies.
Ivy Garth
Sustainable Seed Co. www.ivygarth.com
sustainableseedco.com Broker
Large collection of small grains and vegetable
seed, many organic varieties. Pacific Plug and Liner
www.ppandl.com
Territorial Seed Co. Producer of huge selection of annual and
www.territorialseed.com perennial plugs.
Vegetable, flower, and herb seeds, garlic bulbs,
some supplies, geared to smaller-scale growers. Pioneer Gardens
www.pioneergardens.com
Wild Garden Seed Producer of quality plugs and bareroot
www.wildgardenseed.com perennials.
100% organic and open pollinated seeds, many
unique greens and other vegetables, with a focus C. Raker & Sons
on varieties geared to the Pacific Northwest. www.raker.com
Growers of vast collection of annual and
perennial plugs and liners.
Resources Unit 1.3 | Part 1 – 143
Propagation/Greenhouse Management
Skagit Gardens Hummert International
www.skagitgardens.com www.hummert.com
Growers of an extensive of collection of annual Supplier of a huge array of equipment and
and perennial plugs. supplies for greenhouse production, including
germination chambers, soil media mixing
Speedling Inc. equipment, vacuum seeders, wand seeders,
www.speedling.com bench systems, ventilation, heating and cooling
Producer of vegetable transplants and many equipment.
ornamentals for commercial growers.
Johnny’s Selected Seeds
SUPPLIERS www.johnnyseeds.com
Offers a wide range of tools and growing
Agra Tech Inc. supplies.
www.agratech.com
Manufacturer of greenhouses, high tunnels, and J M McConkey
distributor of environmental controls systems, mcconkeyco.com
heating and cooling devices. Manufacturer and distributor of nursery pots,
paks, and carrying trays, lightweight plug trays,
Anderson Pots shade cloth, weed fabric, and environmental
www.andersonpots.com controls for greenhouses and high tunnels.
Manufacturer of a wide range of nursery
pots, carrying trays, and heavy-duty plastic Peaceful Valley Farm Supply
propagation flats. Products widely available www.groworganic.com
through distributors listed on their website, Supplier of a full range of materials to support
direct sales to licensed resellers. organic growers: Tools, vegetable and flower
seeds, cover crop seeds, fertility inputs, pest,
Carolina Greenhouses disease, and weed control supplies, growing
www.carolinagreenhouses.com/page/ containers, bare root trees, garlic.
page/1872691.htm
A supplier and manufacturer of a full range of Speedling, Inc.
greenhouse structures, environmental controls, www.speedling.com/eps.html
germination chambers, Speedling trays. Supplier of Speedling EPS plug trays direct from
the manufacturer.
Crop Production Services
www.cpsagu.com Stuewe & Sons
A nationwide company supplying growers with www.stuewe.com
fertility inputs, pest and disease control supplies, Supplier of “conetainers,” plug trays,
greenhouse films, weed barrier, cloth, growing propagation trays and vacuum seeder
containers. Supplier to both conventional and equipment. Geared toward the forestry industry,
organic growers. but widely applicable for greenhouse growing
supplies.
Farm Tek
www.farmtek.com Stuppy Greenhouse
Distributor of greenhouses, high tunnels, www.stuppy.com
heating and cooling equipment, controllers, and Greenhouses, high tunnels, glazing and shade
growing supplies. cloth, control systems, heating and cooling,
bench systems.
Part 1 – 144 | Unit 1.3 Resources
Propagation/Greenhouse Management
SUPPLEMENT 1
Examples of Cool- & Warm-Season Greenhouse
Management in a Passive Solar Greenhouse
Greenhouses modify environmental conditions to optimize plant health and growth. In
passive solar greenhouses, the greenhouse manager uses a combination of techniques to
moderate temperatures, moisture levels, and air circulation. Here we offer some examples of
cool– and warm-season greenhouse management methods used at the UC Santa Cruz Farm’s
greenhouses.
Cool Season Greenhouse Management mal plant health. This is especially true during the
ungerminated, germinating, and very young seedling
Sunlight, appropriate irrigation, temperature stage of development.
management, and air circulation are of paramount
importance during the cooler period of limited n When the weather is consistently cool and/or
sunlight. overcast, water loss through the stomata and evapo-
ration from the soil surface (together called evapo-
SUNLIGHT transpiration), water uptake by plant roots, and rates
of plant growth are at a minimum. Thus, we can and
During the winter, prime plant growth by way should wait much longer between waterings.
of photosynthesis takes place principally between
9:30 am and 2:30 pm. While we cannot control the n Allowing a more significant wet-to-dry swing
amount of sunlight available to plants during the of and near the soil surface is one of the primary
cool season, we can optimize crop use of what light cultural tools we have to prevent the presence and
is available by working with the microclimatic dif- proliferation of damping off organisms. Once estab-
ferences within our greenhouse structures. lished, damping off fungi will kill many vulnerable
species. Facilitating a wet-to-dry swing is absolutely
n The impacts of nearby trees, buildings, and critical for all large-seeded crops: Cucurbits, le-
greenhouse infrastructure may all be exaggerated in gumes, sunflowers, etc.
the winter and early spring; plants and containers
should be placed so as to optimize growth. n Water is best delivered during the warmest
portion of the day, usually between 11 am and 2
n It may be necessary to turn flats/containers pm. Don’t water first thing in the morning, to avoid
180° 1–2 times per week to compensate for photot- dropping soil temperatures, or late in the day, also
ropism, the natural leaning of plants towards avail- to keep soil temperature up and to allow time for
able sunlight. Phototropism is a common challenge some dry down before the air temperature drops.
in the winter due to the sun’s low trajectory as it
moves from east to west. n Water temperature should be approximately
the same temperature as the air to avoid significant
n Typically, recent prickouts (seedlings that have soil temperature fluctuations. Applying 45° water to
been transplanted to larger containers) don’t need 65° soil will cool soil significantly and rapidly. Soil
shade protection, and can be immediately returned temperatures are slow to rebound during the cool
to one of the greenhouses. However, if we are expe- season, which slows down germination and root
riencing a heat wave or a pattern of intense sunlight, growth.
prickouts will need to be held over in the shade for
2-4 days to minimize transplant shock. n Water lightly and more frequently—the op-
posite of the summer pattern. The only common ex-
n If necessary, cleaning the glass/plastic glazing ception is crops growing on bottom heat, such as the
increases sunlight penetration. solanums, which are drying from above and below
and thus need deeper, but less frequent watering.
WATERING
n It is easier to go back and add more water if
Cool season conditions dictate a more conserva- things are drying down quickly, but impossible to
tive approach to watering in order to ensure opti-
Supplement 1: & Cool- and Warm-Season Greenhouse Management Unit 1.3 | Part 1 – 145
Propagation/Greenhouse Management
“subtract” water if once your soil is overly wet. mately the optimal temperature range for warm
Under more extreme weather conditions it can take season crops and close to the range for cool season
upwards of a week to achieve adequate dry down. crops. Always sacrifice air temperature in favor of
air movement.
n One watering a day is usually the maximum.
Check depth of water penetration before and after Cool season venting is more nuanced than in the
watering, especially if flats are very dry. summer. More frequent and slight adjustments are
often necessary to balance proper airflow and main-
TEMPERATURE MANAGEMENT tain ideal temperatures.
Temperature management in a passive solar Typical venting pattern on cool/clear days in Santa
structure is a balancing act between heating and Cruz, California:
cooling. Heating occurs via solar radiation/trapped
air mass as dictated by available sunlight. Cooling 10:00-10:30: Open bottom vents and crack
happens by way of ventilation, or the importation ridge vent to allow air circulation and prevent
of cool exterior air into the “heated” greenhouse rapid temperature spiking
environment.
11:30-1:30: Adjust venting as necessary to
n Managing temperatures is a sophisticated maintain optimal temperatures and water as
art that requires careful attention to daily weather necessary
patterns, awareness of changes in sunlight intensity
over the course of the day, and attention to fluctua- 3:00-3:30: Close vents 1-half to 1 hour before
tions in outside air temperatures. sun moves off of the house. Exact timing will
change as days lengthen
n As greenhouse managers we must use this
heightened awareness to manipulate venting ap- To maintain warmer temperature on cool, over-
propriately, thus maintaining optimal temperature cast or rainy days, venting will be minimal, but still
conditions within the greenhouse. In a greenhouse crucial to facilitate air exchange and prevent the
filled with diverse crops, target temperatures are: stale/dank conditions that allow damping off organ-
isms to proliferate and prosper.
Daytime temperature range: 60-80°
Typical venting pattern on cool/overcast/rainy days:
Optimal temperature: 65-75°, 70-85° for warm
season crops 9:00-10:00: Crack ridge vent and open side
vents for approximately one half hour
Nighttime temperature range: 55-60°
10:00-12:00: Water only if absolutely necessary
n Temperatures greater than 50° are needed for
steady/stocky growth. 11:00-12:00: Again crack ridge vent and open
side vents for approximately one half hour
n Temperatures greater than 85°, if not sustained
for more than a few hours, such as when vents are 1:00-2:00: Again crack ridge vent and open side
closed in the afternoon, should not be a problem. In vents for approximately one half hour
fact, this spiking is necessary in a passive structure
to allow for a buffer and the gradual dissipation of 2:30-3:00: Close vents half to 1 hour before
heat into the evening, rather than an abrupt drop in sun moves off of greenhouse. Exact timing will
temperature as the sun passes off of the greenhouse. change as days lengthen. Do not water.
n Winter concerns: Too cool/too wet. Damping Horizontal Air Flow (HAF) fans should be on
off occurs during extended wet and cool periods. whenever vents are closed and always left on at
Always sacrifice air temperature in favor of air night.
movement.
Typical venting pattern on warm/clear days:
VENTILATION/AIR CIRCULATION
9:00-9:30: Crack ridge vent and open side vents
Airflow is critical to avoid damping off, which
can be a problem when we have consecutive cool, 10:00-11:00: Open ridge vent halfway to fully
wet gray days with little day/night temperature open, leave door wide open. Water as necessary
fluctuation. 68º–86º is the optimal temperature for or wait until midday.
damping-off fungi to thrive. This is also approxi-
12:00-1:00: If not already wide open, consider
opening vents fully and deliver water as
necessary
Part 1 – 146 | Unit 1.3 Supplement 1: & Cool- and Warm-Season Greenhouse Management
Propagation/Greenhouse Management
3:00-4:00: Close all venting and doors half to 1 Typical venting pattern on warm/clear days
hour before sun moves off of house. Exact timing (65-75º):
will change as days lengthen.
By 8:30 am: Open the ridge vent to 6” and open
ANTICIPATE—READ AND REACT sides
n Close the greenhouse earlier when you antici- By 10:00 am: Fully open ridge vent and leave
pate cold nights. Closing early and the consequent door wide open
temperature rise will help retain warmth longer into
the night. 5:30-6:00 pm: Close all venting and doors,
knowing that temperatures will climb. Be sure
n Be aware of 3–5 day weather forecasts to assist plants have adequate moisture to get through
in venting and watering decisions. Check NOAA the night. Be sure all side vents are closed and
online weather information or other reliable source turn on HAF fans.
to help anticipate what to do and when to do it.
To maintain appropriate temperature on cool,
Warm Season Greenhouse Management overcast, or foggy days, venting can begin a bit later
in the morning and may not require the ridge vents
As with cool season conditions, maintaining a good to be fully open, but venting is still crucial to facili-
wet-to-dry swing is critical during the warm season. tate air exchange and prevent the stale/dank condi-
Ventilation is the primary means to regulate tem- tions that allow damping off organisms to prolifer-
perature and maintain circulation. ate and prosper.
WATERING Typical venting pattern on cool/overcast/foggy days
(50-65º):
In summer, water plants as needed. As a general
cultural practice, water earlier in the day so there is 9:00-ish am: Crack ridge vent to 6” and open
time for plants to dry down some before the evening side vents
while still having enough moisture to get through
the night. If you are closing on a hot day and plants 11:00 am: Open ridge to halfway open
have dried down too much, water them as needed.
If it is a plant susceptible to damping off, water 12:30-1:00 pm: Open ridge vent fully if inside
conservatively. temps are >75º
There are 4 main watering “pushes”: 2:30-3:00 pm: Return ridge vents to halfway
n Morning open
n Midday (expect to water through lunch time)
n Mid Afternoon (3:00) 5:00-5:30 pm: Close all vents. Turn HAF fans on.
n Evening (5:00) on a HOT day
Typical venting pattern on hot days (outside temps
VENTILATION predicted to be >80º and no fog):
Ventilation is the primary tool for cooling, so in By 8:00 am: Open side and ridge vents fully.
warmer weather it is critical to proactively vent to Keep vents and doors wide open all day
keep temperatures from climbing. At its most basic,
warm season venting simply involves opening and As late as 6:30-7:30 pm: Close ridge and side
closing at the proper times. The recommendations vents. Turn on HAF fans.
below are intended as a guide. Use your senses,
intuition, and knowledge of the current weather Consider wetting down the floors to facilitate
conditions as your primary indicator of what to do evaporative cooling if greenhouse temperature ex-
and when to do it. ceeds 90º.
Based on anticipated weather pattern, consider
moving out all cool season crops, especially lettuces,
brassicas, larkspur, stock, etc. to protect crops from
thermodormancy and other heat-induced stress.
Supplement 1: Cool- and Warm-Season Greenhouse Management Unit 1.3 | Part 1 – 147
Propagation/Greenhouse Management
SUPPLEMENT 2
Conserving Water & Protecting Water Quality
A number of simple, straightforward, and easy-to-implement greenhouse practices will help
conserve water and protect water quality while enhancing the health of your plants.
Water Conservation Tips operation. Consider implementing ways to protect
water quality:
n Use a soil mix that includes ingredients such as
compost and coco peat, which hold water effectively n Just as you do in the field or garden, try and
so that you don’t have to irrigate as frequently. Just meet the plants’ nutrient needs without overfertiliz-
as with soil, you want a media that holds water but ing. Too much fertility can make your starts vulnera-
doesn’t get waterlogged. ble to pests and diseases, as well as lead to nutrients
lost in runoff water. To minimize nutrient loss from
n Understand the natural cycling of water in the soil mix of your perennials, use a stable, slow
your soil mixes, and how water use changes under release nutrient source, e.g., compost.
different environmental conditions. By being aware
of the rates at which your developing plants use n Some nurseries use an “ebb and flow” irriga-
water you can respond with sufficient irrigation but tion system; plants are set in a basin and wick water
avoid overwatering. up from below. Once the plants are irrigated, the
remaining water is drained off to reuse, thus sav-
n Water in advance of your plants’ needs: early ing water and “recycling” any leached nutrients.
in the day when they can get fully hydrated and not The potential drawback to this system in an organic
lose water to evaporation. If plants are on outdoor operation is that if diseases are present there’s a risk
benches, avoid watering during hot, windy condi- of spreading them amongst the plants.
tions to minimize evaporation.
n Water can pick up particulate matter from
n Be conscious of the amount of water you’re ap- potting soil and other growing media and deposit it
plying, especially to Speedling/plug trays and gallon into your water supply; this is true of both organic
pots. You need to wet the plants’ roots but don’t let and conventional mixes. Figure our where the runoff
excessive water run through the containers and onto is going: Can it be directed to crops or non-crop
the ground. vegetation that would benefit? For example, can it
irrigate a windbreak or hedgerow that will cycle
n “Block” or organize your trays of plants in the nutrients, rather than having nutrients running off
greenhouse by life stage and irrigation needs. Group site into surface or groundwater?
those that can dry down between waterings and
those that need more consistent irrigation. n Develop a system that captures all your runoff
(greenhouse roof, benches, and floors, hardening off
n Leave a minimum of space between plant trays tables, outdoor sites where perennials are watered,
to limit watering empty tabletops and bare ground. etc.) and put it through a biofilter or sand filtration,
store it in a pond or tank, and then reuse that same
n Whatever your water delivery system (fixed water. Although potentially expensive, such a system
spray, boom irrigation that moves on a track over could be eligible for funding from the Natural Re-
the tables, or hose/watering can with a rose), make sources Conservation Service’s Environmental Qual-
sure it is sized to match your tables/benches so that ity Incentive Program (EQIP) to encourage water
you’re not spraying the walls and floors. conservation and protect water quality.
n Make sure to have shutoffs on all your hoses. In To minimize the risk of introducing pesticides
a greenhouse or outside, e.g., when irrigating potted and herbicides into the water supply, manage envi-
up perennials, use “zonal shutoffs” for fixed irrigation ronmental conditions to reduce pests and diseases.
systems so that you only water areas that have plants. Emphasize cultural controls and biological controls
before using controls such as soaps, oils, and Neem
Water Quality Considerations (a broad spectrum insecticide and fungicide).
Using water efficiently and avoiding unnecessary Supplement 2: Conserving Water & Protecting Water Quality
runoff will also help protect water quality. But
inevitably, there will be runoff from your greenhouse
Part 1 – 148 | Unit 1.3
Propagation/Greenhouse Management
SUPPLEMENT 3
Low-Cost & Sustainable Alternatives to
Traditional Greenhouse Propagation
Seed propagation is one of the most important—and potentially expensive—processes for a
successful farm or garden. In agroecological systems that rely heavily on transplanting for
some crops, continuous propagation in the greenhouse is crucial for successive cropping.
The greenhouses, growing containers, and growing Seed saving requires some botany and ecology
media needed to grow healthy transplants are not knowledge to preserve varietal integrity. It also
only costly, adding to the already high initial capital requires additional in-ground time commitment for
investment required to begin a farming operation, most crops as well as the labor to harvest, process/
but also use large quantities of non-renewable re- clean saved seed.
sources. As input costs and impacts continue to rise
worldwide, farmers need to find alternative sources As discussed in Supplement 1 in Unit 1.4, by
of energy and inputs to support their plant’s grow- saving seed you can select for plants adapted to lo-
ing needs. cal climate and soil features, and maintains genetic
diversity in an era when genetic engineering and hy-
Although many of the costs related to farming brid technology threaten crop diversity worldwide.
that make it financially risky are fixed or inelastic, By saving seed, farmers can lower overall operat-
meaning they are difficult to change (e.g., land rents, ing costs as well as supply the farm with its own
water costs, fossil fuel costs), there are some that organic, locally adapted seed.
can be minimized. Without easy access to govern-
ment-subsidized credit, it is essential that organic Seed saving can be a central part of developing
farmers (new ones especially) minimize costs wher- a closed-loop system, minimizing external depen-
ever possible to make their operation economically dence and enhancing the process of community seed
viable. Likewise, in urban areas where fixed costs sovereignty. These benefits and challenges should be
may be even higher and access to raw materials and carefully weighed against the cost and convenience
farmer know-how is limited, low-cost alternatives to of buying seed from existing sources.
traditional greenhouse propagation that include do-
it-yourself options can mean the difference between Passively Solar Heated Greenhouses
success and struggle, and often provide more envi-
ronmentally sustainable and socially just solutions. The greenhouse is by far the largest propagation-
related investment for a farmer. Most commercial
Here are a few options for greenhouse propaga- greenhouses are expensive to buy or have built, and
tion that reduce the costs, and in turn the barriers, often maximize only the sun’s light energy while
to starting a farm or market garden. relying on fossil fuels in the form of electrically pow-
ered vents, fans, lights, heating tables, and thermo-
Seed Saving stats to moderate heat. Passive solar greenhouses, on
the other hand, are designed to maximize use of the
Seed saving not only reduces the cost of propaga- sun’s light and heat energy with little to no reliance
tion, it provides adaptive on-farm benefits and pre- on other sources of energy to control temperature or
serves genetic diversity. Saving seed also embodies air circulation. Passive solar heating relies on maxi-
the philosophy of sustainability that guides agro- mizing sunlight during the day and then storing the
ecological farming. Seed costs, while not the largest trapped heat overnight using a thermal mass, usually
operating expense on a farm, can be significant, es- large drums of water, blocks of stone, or gravel
pecially when the cost of cover crop seed is factored beds, within the greenhouse.
in. Additionally, there is a price differential between
conventional and organic seed—and organic seed Besides their use of “free” energy from the sun,
for a number of varieties isn’t always available, even passive solar greenhouses are relatively inexpensive
from commercial organic seed companies. to build when compared to commercial greenhouses
Supplement 3: Alternatives to Traditional Greenhouse Propagation Unit 1.3 | Part 1 – 149
Propagation/Greenhouse Management
and can be built by someone without extensive Sustainable Propagation Potting Mixes
construction experience. Building a greenhouse inde-
pendently not only reduces one of the few variable Growing media used in propagation often rely on
capital costs in starting a farm, but also allows the soilless mixes to minimize disease risks from soil
farmer to customize the design for her/his specific borne pathogens. Unfortunately, the most common
location, climate, and production goals. ingredients in these mixes often originate hundreds
or thousands of miles off-farm and require envi-
Shared Propagation Infrastructure ronmentally destructive processes to produce (see
Lecture 4). Standard mixes in organic agriculture
For new farmers, and urban farmers in particular, (including those used at the CASFS Farm & Gar-
finding the resources and in some instances the space den) include compost, sand, perlite, vermiculite, and
for greenhouse propagation can be a challenge. coconut coir. Other than compost, all other materi-
Some farms contract with commercial nurseries als are purchased as needed. Perlite and vermiculite
or larger farms with available greenhouse space to are strip-mined materials and coconut coir is a by-
grow their seedlings. While this may provide some product of coconut production, originating mainly
benefits, including saving time, labor, and the need in India and Sri Lanka. Aside from the added cost
for propagation infrastructure, another approach of purchasing off-farm inputs, these materials carry
is to share the costs of building and maintaining a an embedded energy and environmental cost that
greenhouse with other local farms or gardens. If no detracts from the sustainability of an agroecologi-
other farms in the area share this need, then finding cal farm. While not yet certified for use in organic
a nearby greenhouse from which the farmer can bor- systems, Growstones offer one alternative to the
row or rent space is an alternative. widely used, but unsustainably sourced perlite
in potting media. Lecture 4 describes additional
While sharing greenhouse space may be logisti- materials that may be more sustainable sourced and
cally challenging, perhaps more so in rural areas serve the save function.
than in urban areas, there are several benefits to this
arrangement. Most importantly, each farmer can
control her/his propagation process, materials, and
irrigation. In urban settings, farmers and gardeners
can use the greenhouse as a communal space to share
information and techniques, as well as an education-
al resource on self-sufficiency for urban populations.
Part 1 – 150 | Unit 1.3 Supplement 3: Alternatives to Traditional Greenhouse Propagation
Propagation/Greenhouse Management
Glossary
Aeration Endosperm
To add oxygen The starch- and oil-containing tissue of many
seeds used by the seedling in the initial stages
Annual of development prior to the beginning of
A plant that completes its life cycle (germination photosynthesis
through death) in one year or growing season,
essentially non-woody F-1 Hybrid
A plant resulting from a cross between two
Asexual propagation genetically distinct individuals, which allows
Propagation by vegetative means, rather than by for the combination and expression of desirable
seed. Not sexual, i.e., not involving the fusion of traits in the F-1 generation
male and female sex cells.
Fertigation
Biennial Fertilizer delivered through irrigation equipment
A plant completing its life cycle (germination
through death) in two years or growing seasons Fertilization
(generally flowering only in the second) and The use of concentrated forms of nutrients
non-woody (at least above ground), often with a (e.g., fish emulsion to deliver soluble sources of
rosette the first growing season) nitrogen)
Cell Tray Hardening Off
Multi-cell propagation container, also known as The process of gradually exposing greenhouse-
“plug tray” raised transplants to field conditions resulting in
the development of more resistant and resilient
Cotyledon seedlings
Seed-leaf; a modified leaf present in the seed,
often functioning for food storage. Persistent in Imbibation
some annuals and helpful in their identification. The process of water absorption by a dry
substance or structure, causing it to swell
Cross pollination
The transfer of pollen from one flower to Monocot
another, either on the same plant or between Flowering plant having one cotyledon (e.g., lily,
compatible plants, to effect fertilization and the orchid, grass, cat-tail, palm)
seed development
Open pollination
Dicot The placing of pollen on a stigma or stigmatic
Flowering plant having two cotyledons (e.g., surface by natural means, e.g., insect, wind, etc.
poppy, cactus, rose, sunflower)
Perennial
Damping Off A plant with a life cycle of more than two years
A fungal pathogen whose populations are
encouraged by consistently high moisture levels Photoperiodism
in the propagation media and high humidity. The response of a plant to the relative duration
Negatively affect developing seedlings, often of day and night, especially in regard to
leading to lodging. Presence indicated by brown flowering
ring of compromised tissue around stem of
plant. Often leads to losses. Plumule
The young shoot as it emerges from the seed on
Embryo germination, usually after the appearance of the
An immature plant within a seed radicle
Glossary Unit 1.3 | Part 1 – 151
Propagation/Greenhouse Management
Pricking Out Sexual Propagation
A traditional French-intensive method of raising The intentional reproduction of a new
seedlings in wooden flats, where seedlings are generation of plants by the germination and
transplanted from a sowing flat at high density growth of seeds that were created in the
to a second propagation flat at lower density previous generation through the fertilization of
a plant ovary via the union of male and female
Propagation Media sex cells. Results in a genetically unique plant
The growing media in which seeds are generation.
germinated and seedlings are grown
Stratification
Radicle The exposure of ungerminated seeds to either
The young root as it emerges from the warm or cold temperature extremes to release
seed, normally the first organ to appear on chemical dormancy factors
germination
Transpiration
Roguing The loss of water vapor from a plant, mostly
The selective removal of seedlings affected by from the stomata of leaves
pests or pathogens
Viability
Scarification Capability of germination
Scratching or etching a thick seed coat to
improve water uptake
Self Pollination
Self pollination occurs when pollen is
transferred from the anther to the stigma of the
same flower
Part 1 – 152 | Unit 1.3 Glossary
Propagation/Greenhouse Management
Appendix 1: Characteristics of Open-Pollinated
(OP) & Hybrid Seed
Open-pollinated seed is produced when the F1 Hybrid seeds are the product of deliberate,
flowers are fertilized by pollen from within a genetically controlled cross pollination of two genetically different,
stable population. Offspring grown from open- but homogeneous, inbred, stable parent lines, each of
pollinated seed bear traits or qualities that closely which contribute enhanced, desirable characteristics to
resemble the parent population. Open-pollinated seeds the subsequent F1 generation. Seeds saved from this
may come from: next generation, the F2 filial line, typically possess a
highly heterogeneous characteristics and will produce
Self-pollinated populations, which are typically of highly variable offspring unlike the hybrid parent
a stable homozygous genetic makeup, thus limiting population.
problems of lack of vigor associated with inbreeding
depression. Self pollination occurs when pollen is Advantages
transferred from the anther to the stigma of the same Homogeneity, uniformity, and predictability of
flower. This pollen germinates and grows down the characteristics throughout the F1 population (for
style, to effect fertilization within the ovary of an example: Vigor, uniformity, flavor, high yield, earliness,
individual flower. lateness, pest and or disease resistance, fruit quality,
storage ability, etc.)
Cross-pollinated populations, which are typically
heterozygous in genetic makeup, and maintain Disadvantages
their vigor and adaptability through the sharing of n I f new pest or disease issues arise, the genetic
genetic information within a stable population. Cross
pollination within stable OP populations occurs when uniformity of F1 hybrid populations may mean
pollen is transferred between different flowers, either that the population lacks ability or the necessary
on the same plant or between compatible plants, to resistance to adapt to new challenges
effect fertilization and the seed development. Cross n S eed saved from F1 Hybrids will produce highly
pollination may be carrid out by insects, mammals, variable, unpredictable populations in the F2
wind, water, or by hand. Cross pollination can occur generation
within a stable population, leading to predictable n I n the F2 generation, populations typically display
results, or it can occur when distinct but compatible the full range of characteristics, both dominant and
populations cross, leading to less predictable results. recessive, that were present in the parent lines used
The generation that results from this cross pollination to create the F1 generation. While individuals within
will display characteristics of the parent population, the F2 population may possess many desirable
whether stable or distinct. characteristics, uniformity and predictability of traits
across the population will normally be absent.
Advantages n C omplex, controlled breeding process and the need
n G enetic diversity within open pollinated populations to maintain distinct parent lines makes it difficult for
growers to produce and save their own F1 hybrid
potentially provides a measure of naturally occurring seeds
resistance and adaptability to pests, pathogens, n T he complexity and labor involved in maintaining
climate shifts, etc. distinct parent lines and in controlling pollination to
n B y maintaining appropriate isolation procedures to produce seeds make F1 Hybrid seed more expensive
preserve varietal integrity and adequate population to purchase
sizes to prevent inbreeding depression and maintain
vigor, open pollinated seed of most crops can be For more information on F1 hybridization, see the
easily and inexpensively produced and saved Royal Horticultural Society website:
www.rhs.org.uk/Advice/Profile?PID=710
Disadvantages
n I n certain species uniformity, yield, and overall
performance may not match that of hybrid varieties
from F1 parent lines
Appendix 1: Characteristics of Open-Pollinated & Hybrid Seed Unit 1.3 | Part 1 – 153
Propagation/Greenhouse Management
Appendix 2: Seed Viability Chart
WITH NO SPECIAL IN CONSISTENTLY
STORAGE CONDITIONS COOL/DRY CONDITIONS
SEED TYPE (YEARS) (YEARS)
Beans, all 2–3 4–6
Beets 2 3–4
Broccoli 2 4–5
Brussels Sprouts 2 4 – 5
Burdock 2 4 – 5
Cabbage, regular 2 4–5
Cabbage, Chinese 3 5–8
Cantaloupe 3 – 4 6 – 10
Carrot 1 – 2 3–5
Cauliflower 2 4–5
Celery 1 – 2 3–5
Collard 2 4–5
Corn, all 1 – 2 4–6
Cucumber 3 5–7
Eggplant 1 – 2 3–5
Endive/Escarole 2 3–4
Kale 2 4–5
Kohlrabi 2 4–5
Leeks up to 1 2–4
Lettuce 1–2 3–4
Mustard 2 – 3 5–8
Onion up to 1 2–4
Parsley 1 – 2 3–5
Parsnip up to 1 1–3
Peas 1 – 2 4–6
Pepper 1 – 2 3–5
Potato (true seed) 2 – 3 5–7
Pumpkin 1 – 2 3–5
Radish 2 3–5
Rutabaga 2 3–5
Salsify 2 3–4
Scorzonera 2 3–4
Spinach 1 – 2 3–4
Squash 1 – 2 3–5
Strawberry 2 – 3 3–6
Sunflower 2 4–6
Swiss Chard 2 3–4
Tomato 2 – 3 4–7
Turnip 2 – 3 5–8
Watermelon 2 – 3 4–6
Part 1 – 154 | Unit 1.3 Appendix 2: Seed Viability Chart
Propagation/Greenhouse Management
Appendix 3: Soil Temperature Conditions for
Vegetable Seed Germination
VEGETABLE MINIMUM (°F) OPTIMUM RANGE (°F) OPTIMUM (°F) MAXIMUM( °F)
Asparagus 50 60 – 85 75 95
Bean 60 60 – 85 80 95
Bean, lima 60 65 – 85 85 85
Beet 40 50 – 85 85 95
Cabbage 40 45 – 95 85 100
Carrot 40 45 – 85 80 95
Cauliflower 40 45 – 85 80 100
Celery 40 60 – 70 701 851
Chard, Swiss 40 50 – 85 85 95
Corn 50 60 – 95 95 105
Cucumber 60 60 – 95 95 105
Eggplant 60 75 – 90 85 95
Lettuce 35 40 – 80 75 85
Muskmelon 60 75 – 95 90 100
Okra 60 70 – 95 95 105
Onion 35 50 – 95 75 95
Parsley 40 50 – 85 75 90
Parsnip 35 50 – 70 65 85
Pea 40 40 – 75 75 85
Pepper 60 65 – 95 85 95
Pumpkin 60 70 – 90 90 100
Radish 40 45 – 90 85 95
Spinach 35 45 – 75 70 85
Squash 60 70 – 95 95 100
Tomato 50 60 – 85 85 95
Turnip 40 60 – 105 85 105
Watermelon 60 70 – 95 95 105
1Daily fluctuation to 60° F or lower at night is essential.
Compiled by J.F. Harrington, Dept. of Vegetable Crops, University of California, Davis.
Source: Knott’s Handbook for Vegetable Growers, by Donald Maynard and George Hochmuth,
Wiley & Sons, Inc., 1997. Used by permission of Wiley & Sons, Inc.
Appendix 3: Soil Temperature for Seed Germination Unit 1.3 | Part 1 – 155
Propagation/Greenhouse Management
Appendix 4: Days Required for Seedling
Emergence at Various Soil Temperatures
from Seed Planted 1/2-inch Deep
VEGETABLE 32° 41° 50° 59° 68° 77° 86° 95° 104°
Asparagus NG NG 53 24 15 10 12 20 28
Bean, lima — — NG 31 18 7 7 NG —
Bean snap NG NG NG 16 11 8 6 6 NG
Beet — 42 17 10 6 5 5 5 —
Cabbage — — 15 9 6 5 4 — —
Carrot NG 51 17 10 7 6 6 9 NG
Cauliflower — — 20 10 6 5 5 — —
Celery NG 41 16 12 7 NG NG NG —
Corn, sweet NG NG 22 12 7 4 4 3 NG
Cucumber NG NG NG 13 6 4 3 3 —
Eggplant — — — — 13 8 5 — —
Lettuce 49 15 7 4 3 2 3 NG NG
Muskmelon — — — — 8 4 3 — —
Okra NG NG NG 27 17 13 7 6 7
Onion 136 31 13 7 5 4 4 13 NG
Parsley — — 29 17 14 13 12 — —
Parsnip 172 57 27 19 14 15 32 NG NG
Pea — 36 14 9 8 6 6 — —
Pepper NG NG NG 25 13 8 8 9 NG
Radish NG 29 11 6 4 4 3 — —
Spinach 63 23 12 7 6 5 6 NG NG
Tomato NG NG 43 14 8 6 6 9 NG
Turnip NG NG 5 3 2 1 1 1 3
Watermelon — NG — — 12 5 4 3 —
NG = No germination, — = not tested
Adapted from J.F. Harrington and P.A. Minges, Vegetable Seed Germination, California Agricultural Extension
Mimeo Leaflet (1954).
Source: Knott’s Handbook for Vegetable Growers, 1997, John Wiley & Sons, Inc. Used by permission of John
Wiley & Sons, Inc.
Part 1 – 156 | Unit 1.3 Appendix 4: Days Required for Seedling Emergence
Propagation/Greenhouse Management
Appendix 5: Approximate Monthly
Temperatures for Best Growth & Quality of
Vegetable Crops
Some crops can be planted as temperatures approach the proper range. Cool season crops grown in the spring
must have time to mature before warm weather. Fall crops can be started in hot weather to ensure a sufficient
period of cool temperature to reach maturity. Within a crop, varieties may differ in temperature requirements;
hence this listing provides general rather than specific guidelines.
OPTIMUM °F MINIMUM °F MAXIMUM °F VEGETABLE
55°–75° 45° 85° Chicory, chive, garlic, leek, onion, salsify, scolymus, scorzonera,
shallot
60°–65° 40° 75° Beet, broad bean, broccoli, Brussels sprouts, cabbage, chard,
collards, horseradish, kale, kohlrabi, parsnip, radish, rutabaga,
sorrel, spinach, turnip
60°–65° 45° 75° Artichoke, cardoon, carrot, cauliflower, celeriac, celery, Chinese
cabbage, endive, Florence fennel, lettuce, mustard, parsley, pea,
potato
60°–70° 50° 80° Lima bean, snap bean
60°–75° 50° 95° Sweet corn, Southern pea, New Zealand spinach
65°–75° 50° 90° Chayote, pumpkin, squash
65°–75° 60° 90° Cucumber, muskmelon
70°–75° 65° 80° Sweet pepper, tomato
70°–85° 65° 95° Eggplant, hot pepper, martynia, okra, roselle, sweet potato,
watermelon
Source: Knott’s Handbook for Vegetable Growers, by Donald Maynard and George Hochmuth,
Wiley & Sons, Inc., 1997. Used by permission of John Wiley & Sons, Inc.
Appendix 5: Monthly Temperatures for Best Growth Unit 1.3 | Part 1 – 157
Propagation/Greenhouse Management
Appendix 6: Examples of Propagation
Containers
Cell Tray or Plug Tray
Wooden Flat
Six-Pack
Part 1 – 158 | Unit 1.3 Illustrations by Cathy Genetti Reinhard; not to scale
Propagation/Greenhouse Management Appendix 8: Examples of Propagation Containers
Appendix 7: Propagation Media—
Ingredients & Properties Imparted
INGREDIENT FUNCTION / QUALITIES IMPARTED SOURCE SUSTAINABILITY COSTS / COMMENTS
Peat Moss Canadian peat bogs $$$ • pH 3.5–5.0
• Fungistatic/acidic • N on-renewable by most counts
Perlite Mined silica, volcanic
5–8 lbs/cu ft • H 1020t-ihmoelds idnrgy capacity origin Arizona $$$ • Non-renewable
weight • No CEC1 • No nutrients
Vermiculite Mica from Montana • Energy intensive production
6–10 lbs/cu ft • H 3–204-thimoldesindgrycawpeaicgihtyt North Carolina
• Aeration • Drainage $$$ • Energy intensive production
Compost Produced on-site or • Non-renewable
• Drainage • High CEC purchased
Soil • H 20-holding capacity Requires labor to produce
6–8 times weight On-site • P otential source of weed seed
Sand • Has Mg/K
Quarried, typically Free • Weed seed potential
Leaf Mold • Moisture retention local
(decomposed • Drainage • Nutrients On-site $ • 0.05–2.0mm diameter
leaf litter) • Pathogen suppression • No CEC or nutrients
Coir Fiber Coconut industry
aka Coco Peat • Minerals • Minor NPK byproduct from Free • Required labor to harvest if
• Bulk density Sri Lanka, Madagascar, suitable material exists locally
Grape Seed Philippines, and India
Pomace • Drainage • Aeration Winery byproduct $$ • Hard to handle/break up
• Non-fungistatic
• Serves as peat substitute • T ravels far to Western market
• Acid/fungistatic
• Drainage • H20-holding Time/labor
• Perlite substitute for mixes
• H20-holding • Drainage • Could have high potassium
• Drainage • Aeration
• K source • Minor N
1CEC = Cation Exchange Capacity (see Unit 2.2, Soil Chemistry and Fertility)
$$$ = expensive input
$$ = moderately expensive input
$ = low-cost input
Appendix 10: Propagation Media Unit 1.3 | Part 1 – 159
Propagation/Greenhouse Management
Appendix 8: Sample Soil Mix Recipes
FLAT/SOWING MIX UCSC FIELD SPEEDLING MIX
3 parts compost (sifted .5 inch screen) 2 compost (sifted .5 inch screen)
2 parts soil
1 part sand 1 coir fiber (premoistened)
2 parts coir fiber (premoistened) or 1 part coir fiber
+ 1 part leaf mold (sifted .5 inch screen) 1 vermiculite (medium/fine)
GARDEN SPEEDLING MIX 3 cups blood meal*
2-1/2 compost (sifted .5 inch screen)
1 soil *This amount of blood meal is based on when the
2 coir fiber (premoistened) or 1 coir fiber + 1 leaf measure of one part is equal to a wheelbarrow.
mold (sifted .5 inch screen)
LIQUID SUPPLEMENTAL FERTILIZER
POTTING MIX Using watering can, per gallon of water:
1-1/2 compost
1-1/2 partially decomposed duff 1/4 cup liquid fish emusion
1 used mix
1 sand 1/2 tsp. Kelp powder
1 grape pomace (or used mistbox mix)
1/2 soil Using foliar sprayer:
DRYLAND POTTING MIX Also add 1/4 tsp. sticker-spreader (surfactant),
3 potting mix added last into the tank to avoid excess foaming (see
1 sand Resources section).
1 perlite (or used mistbox mix)
In a bucket, mix ingredients with a small amount of
or water, first making a paste to avoid clumping, and
1 grape pomace then dilute with water for application. For basal
applications, remove spray nozzle end from sprayer
wand.
Fertigation, especially foliar applications, is best
done in the early morning or in the evening.
Part 1 – 160 | Unit 1.3 Appendix 8: Sample Soil Mix Recipes
Propagation/Greenhouse Management
Appendix 9: Pricking Out Technique & Depth
of Transplanting
Gently prick out seedling from densely planted flat, Place seedling in a new flat
carefully separating individual plants/roots planted at lower density
Plants sown at a high density (e.g., 200/flat)
are pricked out into several flats at a lower
density (e.g., 50/flat) to mature
Proper transplanting depth Improper transplanting depth
Illustrations by Cathy Genetti Reinhard; not to scale Unit 1.3 | Part 1 – 161
Propagation/Greenhouse Management
Appendix 9 Pricking Out Technique
Appendix 10: Flat-Grown & Cell-Grown
Seedlings
Flat-grown seedlings at transplant maturity
—note balance of roots and shoots
Cell-grown seedling at transplant
maturity —note balance of roots
and shoots with roots holding
whole root ball together
Part 1 – 162 | Unit 1.3 Illustrations by Cathy Genetti Reinhard; not to scale
Propagation/Greenhouse Management Appendix 10: Flat-Grown & Cell-Grown Seedlings
CROP DATE & SEED CO. & COMMENTS ON PRICKOUT TRANSPLANT 1ST & LAST YIELD OTHER Unit 1.3 | Part 1 – 163
GERMINATION & Propagation/Greenhouse Management
Appendix 11: Propagation & Crop Performance AMOUNT SEED LOT/ SEEDLING GROWTH DATE DATE HARVEST INFO
Records Sheet
SOWN YEAR (IF APPL.) (TO FIELD) DATES
Appendix 11: Propagation & Crop Performance Records Sheet
Appendix 12: Greenhouse Records Sheet
DATE/ PREVIOUS CURRENT WEATHER GREENHOUSE MANAGEMENT OTHER
TIME
HIGH & LOW TEMP CONDITIONS ENVIRONMENTAL ACTIONS
TEMP CONDITIONS TAKEN
Part 1 – 164 | Unit 1.3 Appendix 12: Greenhouse Records Sheet
Propagation/Greenhouse Management
1.4
Transplanting and
Direct Seeding
Introduction 167
Lecture 1: Transplanting and Direct Seeding 169
Demonstration 1: Garden-Scale Transplanting and Direct Seeding
Instructor’s Demonstration Outline 175
Students’ Step-by-Step Instructions 179
Demonstration 2: Hand Transplanted and Tractor-Mounted
Seeding Equipment
Instructor’s Demonstration Outline 183
Assessment Questions and Key 186
Resources 188
Supplement 1: Genetic Engineering and Seed Diversity: Impacts 189
on Farmers and Agricultural Communities
Appendices
1. Field-Scale Transplanting Guide 191
2. Common Transplant Spacings; Common Seeding 192
Rates and Thinning Distances
3. Transplanting and Irrigation Equipment 194
4. Seedlings at Transplant Maturity; Planting Depths 196
5. Estimating Soil Moisture By Feel 197
6. Garden-Scale Seed Bed Irrigation 198
7. Garden Sowing Log 199
8. Garden Transplanting Log 200
9. Field Sowing Log 201
10. Field Transplanting Log 202
Part 1 – 166 | Unit 1.4
Transplanting & Direct Seeding
Introduction: Transplanting & Direct Seeding
UNIT OVERVIEW MODES OF INSTRUCTION
Learning to recognize optimal soil > LECTURE (1 LECTURE, 45–60 MINUTES)
The lecture introduces the basic concepts associated with
moisture and weather conditions, transplanting and direct sowing in the garden and field
grow and prepare healthy seedlings, > GARDEN-SCALE TRANSPLANTING DEMONSTRATION
(1–1.5 HOURS)
properly prepare planting beds, and The garden-scale demonstration outline details the basic
skills and concepts for direct seeding annual crops and
follow up with optimal irrigation, transplanting both annual and perennial container-grown
plants. Following the outline is a set of step-by-step instruc-
weed control, and plant protection tions for students on seedling and soil preparation, direct
seeding, and transplanting techniques.
are keys to successful transplanting
> ASSESSMENT QUESTIONS (0.5 HOUR)
and direct seeding. Assessment questions reinforce key unit concepts and skills
In this unit, a short lecture compares > POWERPOINT
transplanting and direct seeding, including See casfs.ucsc.edu/about/publications and click on Teaching
the benefits of each; reviews the plant, soil, Organic Farming & Gardening.
and environmental conditions to consider
prior to transplanting and direct seeding; LEARNING OBJECTIVES
and briefly addresses post-transplanting/
seeding practices. Two field demonstra- CONCEPTS
tions introduce students to the basic equip- • The optimal physical environment conditions favorable for
ment and practices associated with direct
seeding and transplanting techniques used successful transplanting
in traditional French-intensive garden-
ing, and in small- to medium-scale field • The optimal soil moisture conditions favorable for
production. successful transplanting
Refer to Unit 1.2, Garden and Field Tillage • The optimal seedling development and pre-treatments
and Cultivation, and to Unit 1.3, Propa- necessary for successful transplanting
gating Crops from Seed, and Greenhouse
Management, for additional information SKILLS
relevant to the material presented here. • How to cultivate and prepare a bed appropriate for sowing
seeds of various sizes or for transplanting starts
• How to sow small- and large-seeded crops using hand
methods and push seeders
• How to transplant from a cell tray and flat format
• How to water-in/irrigate recently transplanted seedlings
• How to irrigate seed beds for optimal germination
Introduction Unit 1.4 | Part 1 – 167
Transplanting & Direct Seeding
Part 1 – 168 | Unit 1.4
Transplanting & Direct Seeding
Lecture 1: Transplanting & Direct Seeding
Pre-Assessment Questions
1. What is the difference between transplanting and direct seeding?
2. What are some of the reasons to transplant vs. direct seed crops?
3. What type of crops are better suited to transplanting vs. direct seeding?
4. Why do crops need to be “hardened off” prior to transplanting?
5. What are some of the environmental conditions most conducive to successful
transplanting?
A. Transplanting versus Direct Seeding: Advantages and Appropriateness of Each Technique
1. Transplanting and direct seeding defined
a) “Transplanting” refers to the act of transferring seedlings from containers in the
greenhouse (cell trays, flats, pots, etc.) into the garden or field
b) “Direct seeding” or “direct sowing” refers to planting seeds in the field to germinate in
place
c) Note that there are no hard and fast rules about which crops are transplanted vs.
directly sown; there are advantages and disadvantages to each method, and a number
of factors will play into the decision regarding which approach to use. These include
scale of planting, labor availability, length of season, types of seeders available,
weed management capacity, and greenhouse and land availability. In some cases,
transplanting a difficult-to-transplant crop can pay off if the market offers a premium for
early harvest. See Appendix 1, Field-Scale Transplanting Guide, for recommendations
regarding transplanting vs. direct sowing of various crops.
2. Transplanted crops
a) Advantages of starting crops in greenhouse
i. Greater climate control: Temperature, humidity, water
ii. Soil mix can be tailored to specific crop, as per fertility and drainage capabilities (see
Appendix 8, Sample Soil Mix Recipes, in Unit 1.3, Propagating Crops from Seed, and
Greenhouse Management)
iii. Offers protection from predators and elements: Wind, rain, birds, snails, etc.
iv. Greater season extension (can start crops earlier indoors)
v. Intensive rather than extensive management of seedlings: E.g., one 12” x 24” flat of
leeks can plant a 4’ x 50’ bed with 6 rows at 6”/row (600 seedlings). Fewer resources—
time, water, weeding, etc.—are required to care for 1 flat of leeks vs. 1 direct-sown
bed.
vi. Weed management: Transplanted crops have a better chance at outcompeting
weeds than seeds sown directly in the ground
b) Advantages of using greenhouse-grown transplants
i. Rapid crop successions (e.g., from cover crops to cropping and from one crop to
another), as ground is not “tied up” with developing seedlings
ii. May allow for greater control over specific density of crops; save labor on thinning
iii. Get ahead of weeds (till in or “flame” weeds ahead of transplanting), thus saving labor
on hoeing and weeding (see Unit 1.10, Managing Weeds)
iv. Conserves water: Less water required to irrigate transplants vs. irrigating seed beds
v. Fewer seeds needed to grow starts vs. direct seeding/thinning
vi. Creates better stand: Possible to have almost perfect establishment; less regular if
thinning direct-seeded crops to a stand
Lecture: 1 Transplanting & Direct Seeding Unit 1.4 | Part 1 – 169
Transplanting & Direct Seeding
c) Root nature of transplanted crops: Fibrous roots transplant better than taproots (see
Unit 1.3 for additional details)
d) Examples of transplanted crops: Lettuce, chard, kale, brassicas, fennel, tomatoes,
peppers, fresh onions (in clusters), storage onions, basil (in clusters); at a garden scale,
squash and cucumbers are often transplanted (see Appendix 2, Common Transplant
Spacings; Common Seeding Rates and Thinning Distances for suggested spacings)
3. Direct-sown or seeded crops
a) Advantages of direct seeding
i. Scale of production: Many crops are direct sown on a large scale to avoid costs
associated with greenhouse production and transplanting
ii. Certain crops grow well at high density and/or are more easily harvested at high
density, and are therefore better suited to direct sowing (e.g. cilantro, baby spinach)
b) Root nature of direct-sown crops: Often taprooted crops (e.g. beets, carrots, spinach,
parsnips) are direct sown so as not to disrupt the taproot by transplanting
i. Exceptions: Most crops, including taprooted crops, may be transplanted if sown and
transplanted in clusters
c) Intended density of crops: Direct-seeded crops require sowing at a high density and
eventual thinning (see Appendix 2). Precision seeders, such as Earthway and Jang
(pronounced “yang”), can help reduce the need for thinning in the garden. Other
precision seeders used on a field scale include the John Deere 33 (for small seed) and
John Deere 71 (for large seed). Stanbay seeders are commonly used in large-scale field
production. See illustrations in Appendix 3, Transplanting and Irrigation Equipment.
d) Examples of direct-sown crops: Sweet corn, snap beans, carrots, beets, turnips, spinach,
cilantro, dill
4. “Pelleted” seed
a) Pelleted seed is used in both transplanting and direct sowing. It is coated with a clay-
based material to make it larger, more uniform, and easier to handle.
b) Advantages and disadvantages of pelleted seed
i. The uniform size and shape of pelleted seeds makes them better suited for tractor-
mounted or push seeders, as well as for vacuum seeders in a greenhouse
ii. The “pelleting” process decreases seeds’ length of viability; it is viable for a shorter
time than raw seed
iii. Pelleted seed is more expensive than raw seed
B. “Hardening Off” Period Prior to Transplanting: What It Is and Why It’s Important
1. Hardening-off period (3–30 days) defined: “Hardening off” a transplant refers to making a
gradual transition from greenhouse to outdoor field conditions
2. Physiological adjustments plant makes in the process of hardening off:
a) As seedlings are exposed to increased airflow (wind) and a greater temperature swing,
the cells of the plant “toughen up.” Stems thicken and strengthen, making them more
suitable to field conditions.
3. The hardening-off process:
a) Depending on environmental conditions, a hardening off period might start with
bringing transplants outdoors for a few hours a day in mild conditions and bringing
them in at night for a few days. The length of time the seedlings stay outdoors
is increased gradually over a period of a week or a few weeks. In mild climates, a
hardening off period of 3–4 days may be sufficient.
Part 1 – 170 | Unit 1.4 Lecture 1: Transplanting & Direct Seeding
Transplanting & Direct Seeding
b) Examples of hardening-off progressions:
i. From an enclosed greenhouse to an open-ended hoop house, and then to the field.
ii. From an enclosed greenhouse to tables or pallets under cover (e.g., shade cloth,
plastic, or row cover) that can be rolled up during the day and rolled down at night in
cooler temperatures, and then to the field
C. Assessments of Plant, Soil, and Environmental Conditions Prior to Direct Seeding or
Transplanting
1. Seedling development necessary for successful transplanting
a) Shoot development: Generally 4–6 true leaves; for quick-growing plants such as
lettuce and Asian greens, 2 sets of leaves may be adequate if there is adequate root
development (“root knit”)
b) Root development: Roots should be well developed and branching. If started in a cell
tray, roots should knit together in a well-formed unit that can hold up when pulled
from the cell. In flats, roots should hold together in a root ball without dropping soil
(assuming soil is wet). See Appendix 4, Seedlings at Transplant Maturity; Planting
Depths for illustration of root knit.
2. Seedling pre-treatments necessary for successful transplanting
a) Soil/media moisture: With transplants started in cell trays or in flats, it is best to water
thoroughly soon before transplanting (an hour or less)
i. Flat-grown seedlings: Planting media at 75–80% of field capacity
ii. Cell-grown seedlings: Seedling trays saturated (dripping wet)
b) Thorough watering helps the soil/root ball hold together, and gives the plant a boost
before and during transplanting, which—even when done at optimum conditions—is
still a disruptive event for young plants. By starting with wet roots, planting under
optimum conditions and irrigating immediately/soon after transplanting, the “shock” of
transplanting can be reduced.
c) Alliums are an exception—they can be “bare rooted” during transplanting, and therefore
need drier soil in the cell tray or flat to allow the roots to be separated from each other
and from the planting mix
3. Soil conditions favorable for successful transplanting or direct sowing (see Unit 1.2, Garden
and Field Tillage and Cultivation, for more information on bed preparation)
a) Soil moisture: 75–80% of field capacity at a garden scale; 50–60% field capacity at
field scale to avoid soil compaction when using planting equipment (see Appendix 5,
Estimating Soil Moisture by Feel in this unit, and Unit 1.5, Irrigation—Principles and
Practices, for more on field capacity)
b) Degree of secondary cultivation: Smaller seeds and small transplants such as lettuce
require greater secondary cultivation, i.e. finer tilth. E.g., small-seeded crops such as
carrot seeds need a finely tilled bed for seeds to have adequate soil contact, and for the
cotyledons to penetrate the soil surface.
c) Large transplants, e.g., tomatoes and peppers, can handle less fine tilth as they will not
have to push through the soil surface
4. Optimal physical environment conditions favorable for successful transplanting of flat-
grown seedlings
a) Low light levels, e.g., cloudy or foggy conditions, or late afternoon/early evening.
Planting late in the day gives the plant time to recover and adjust during a period of low
transpiration (night and early morning hours).
b) Low temperatures: Plant in morning or later in afternoon to avoid exposing roots to the
heat of midday
c) Low wind speed
Lecture 1: Transplanting & Direct Seeding Unit 1.4 | Part 1 – 171
Transplanting & Direct Seeding
d) High humidity
e) As environmental conditions are rarely optimal, steps can be taken to reduce stress
by having at least some, if not all, conditions right. E.g., if it is windy, wait until
the temperature is cooler. Or if it is hot, wait until the wind dies down. Irrigating
immediately after transplanting will help the plant recover from stress.
5. Irrigation must be ready to go prior to transplanting; at the field scale, make sure sprinklers
or t-tape are set up before or immediately after transplanting takes place. Transplants
must be watered in immediately after planting to establish root-soil contact and minimize
transplant shock.
D. Additional Field-Scale Considerations
1. Incorporation of cover crop residue through primary tillage (see Unit 1.2, and Unit 1.6,
Selecting and Using Cover Crops)
a) Mowing (flail or rotary)
b) Apply compost prior to residue incorporation, if necessary
c) Incorporate cover crop residue with spader or offset wheel disc
d) Wait an appropriate amount of time for cover crops to break down in the soil (irrigating
can speed this process) so as not to plant into soil with partially-decomposed residue
(usually 2–4 weeks, depending on soil moisture, temperature, and volume of cover crop
residue)
2. Review field soil conditions prior to tillage
a) Soil moisture range: 50–60% of field capacity to avoid soil compaction
3. Establishment of seedbed through secondary tillage techniques
a) Rototill or disc field to improve surface uniformity following residue breakdown. Note
that with some soils/implements, this step can be skipped. E.g., mechanical spading or
multiple passes with a disk can act as both primary and secondary cultivation.
4. Bed formation
a) Form beds with lister bar and shovels or rolling cultivator
b) Shape bed with bed shaper (see Appendix 3)
i. In wet conditions (e.g., coastal California winters), raised beds can improve drainage
ii. In dry conditions, flat beds can minimize drainage
c) Pre-irrigate to germinate weed seed; if using drip tape, pre-irrigate 1 week in advance
d) Cultivate unplanted beds at as shallow a depth as possible with an under-cutter or
“weeder” bar, sweeps, knives, or rolling cultivator to knock back the newly germinated
weeds and reduce weed pressure. See Unit 1.10, for additional information.
e) Ensure good tilth: It is important for roots of transplants to have access to water held in
soil pores; large clods don’t hold water
f ) Plant beds with seeder, transplanter, or by hand
E. Post-Transplanting and Direct Seeding Considerations
1. Irrigation
a) Maintain adequate soil moisture for seeds and transplants: This is particularly critical for
small, direct-seeded crops
i. Garden scale: Microsprinklers, oscillators, or a hose with a watering wand or “rose”
attachment can be used to maintain surface soil moisture; seed beds should be
watered when half the soil surface has dried (see Appendix 6, Garden-Scale Seed
Bed Irrigation). At the depth of the transplant’s root ball (usually 2–4 inches deep)
soil should be watered when it is at the edge of “balling up.” It’s better to apply water
earlier than needed than to wait until the plant is stressed.
Part 1 – 172 | Unit 1.4 Lecture 1: Transplanting & Direct Seeding
Transplanting & Direct Seeding
ii. Overhead irrigation may be appropriate until field crops are established, at which
point it may be appropriate to switch to drip irrigation to minimize water use and
weed growth (see Unit 1.5)
iii. Large-seeded crops and large transplants can be planted to moisture following
irrigation and weed cultivation; irrigation can then be delayed to allow the crop to
get a jump on weed growth (see Unit 1.10)
2. Insect and mammal damage
a) Floating row covers can be used for the first 2–3 weeks after crop emergence or
transplanting to minimize or prevent damage by insect pests (e.g., flea beetles,
cucumber beetles), birds, and mammals: Covers can be placed directly over the crop or
draped over easy-to-make hoops and staked to form low tunnels. After 2–3 weeks crops
are usually large enough, and have developed tougher, less succulent leaves, for the row
covers to be removed (unless pest pressure is intense).
b) Row covers can also help “jump start” warm-season crops such as peppers early in the
season and protect frost-sensitive crops at the end of the season
c) Nutrient needs: In spring, heat-loving crops growing in cool, wet soils may require
supplemental fertility, as nutrients may not be readily available in these conditions.
Supplements may include granular fertilizer (e.g. blood meal, feather meal) or liquid
fertilizer (e.g., fish emulsion, liquid kelp) applied as a foliar spray or soil drench.
Lecture 1: Transplanting & Direct Seeding Unit 1.4 | Part 1 – 173
Transplanting & Direct Seeding
Part 1 – 174 | Unit 1.4
Transplanting & Direct Seeding
Demonstration 1: Garden-Scale Transplanting &
Direct Sowing
for the instructor
OVERVIEW PREPARATIONS AND MATERIALS
• Recently prepared garden bed at 65–80% of field capacity,
The following demonstration outline
covers the basic skills and concepts including a section prepared as fine/particulate surface soil
used to direct seed and transplant for direct sowing of seeds and a section of less particulate
crops for garden-scale production. surface soil for transplanting
Following the outline below, discuss
and demonstrate the tools and • Flats of plants at transplanting maturity with well-
techniques used in garden-scale developed root system (allium and broad-leaf crops)
transplanting and direct seeding, as
well as post-planting considerations • Cell tray at seedling maturity and immaturity
(irrigation, pest control, etc.).
• Hand trowel and hand fork
• Watering wand
• Dibble (see Appendix 3, Transplanting and Irrigation
Equipment)
• Measuring tape
• Rose and hose
• ½” poly line and micro-sprinklers (pre-assembled)
• String, string jig, and stakes (see Appendix 3)
• Large and small seed (e.g., peas/beans and carrots)
• Push seeders: Show different models, if available
• Bed end markers and indelible marker
• Appendices 7 and 8, Garden Sowing Log and Garden
Transplanting Log
PREPARATION TIME
1.5 hours
DEMONSTRATION TIME
1.5 hours
Instructor’s Demonstration 1 Outline Unit 1.4 | Part 1 – 175
Transplanting & Direct Seeding
DEMONSTRATION OUTLINE
A. Assess Plant, Soil, and Environmental Conditions Prior to Transplanting
Briefly review and assess the compatibility of the following environmental conditions and
seedling maturity with the planned tasks, then demonstrate the following:
1. Seedling development necessary for successful transplanting
a) Shoot development
b) Root development
2. Seedling pre-treatments necessary for successful transplanting
a) Soil/media moisture
i. Cell-grown seedlings with media at field capacity
ii. Flat-grown seedlings with media at 75–80% of field capacity
b) Hardening-off period: A minimum of three days of full exposure to field conditions
3. Soil conditions favorable for successful transplanting or direct sowing
a) Soil moisture: Should be 75-80% of field capacity (see Appendix 5, Estimating Soil
Moisture by Feel)
b) Degree of secondary cultivation: Smaller seeds require greater secondary cultivation
4. Optimal physical environment conditions favorable for successful transplanting of flat-
grown seedlings
a) Low light levels
b) Low temperature
c) Low wind speed
d) High humidity
e) Steps to take if environmental conditions are not optimal (see Lecture)
B. Demonstrate Transplanting
1. Plant spacing: Talk about the way the following factors influence crop spacing
a) Pre-irrigation and cultivation considerations
b) Root and shoot size at maturity: Include depth and spread
c) Disease prevention/air circulation
d) References: See Appendix 2, Common Transplant Spacings; Common Seeding Rates
and Thinning Distances of this unit, and Resources section of Unit 1.3, Propagating
Crops from Seed, and Greenhouse Management
2. Tools used to assure uniform plant spacing: Demonstrate tools used to guide planting
a) Parallel lines of string between stakes
b) String jig
c) Transplant marker, e.g., dibble
d) Triangulation
e) One’s hand
3. How to plant: Demonstrate the following
a) Knowledge of crop being planted
b) Plant selection criteria (development and vigor of seedling)
c) Plant handling technique
d) Depth of planting (see Appendix 4, Seedlings at Transplant Maturity; Planting
Depths)
Part 1– 176 | Unit 1.4 Instructor’s Demonstration 1 Outline
Transplanting & Direct Seeding
4. Watering in: Demonstrate why, how, and irrigation options
a) Why? To assure even soil moisture between transplant and surrounding soil in order
to assure uninterrupted regrowth
b) Options for how to irrigate after transplanting (water in)
i. Basal application with watering wand
ii. Overhead sprinkler and considerations of scale
iii. Microsprinkler
iv. Overhead sprinkler, transition to drip irrigation
5. Documenting
a) Demonstrate documenting as learning tool
b) Where to document?
i. Field or bed marker
ii. Garden log book with crop seeding and transplanting dates, variety, and seed
company (see Appendices 7 and 8)
6. Post-transplant follow up
a) Irrigation
i. Method of irrigation: Microsprinklers, oscillators, hand watering
ii. Monitoring root zone for 50–60% of field capacity: At the depth of the root ball
(usually 2–4 inches deep) soil should be at the edge of “balling up.” It’s better to
apply water earlier than needed than to wait until the plant is stressed.
b) Observations of subsequent growth. Discuss the following considerations:
i. Predation: Monitor seedlings for insect or pest damage. Replace as needed. Use
remay or other floating row cover to protect seedlings from insects (e.g., flea
beetles on brassicas and eggplants, cucumber beetles on cucurbits) and from bird
and mammal damage.
ii. Nutrient needs: In spring, heat-loving crops growing in cool, wet soils may
require supplemental fertility such as granular fertilizer (e.g. blood meal, feather
meal) or liquid fertilizer (e.g., fish emulsion, liquid kelp) applied as a foliar spray
or soil drench
iii. Root development: Carefully digging up seedlings to observe root development
provides information for depth of irrigation requirements
c) Excess/replacement seedlings
i. Management of excess seedlings in propagation area: If necessary, pot up “extra”
plants to maintain/extend their viability
ii. Treatment: Supplemental fertility may be required to sustain replacement
seedlings
C. Discuss and Demonstrate Direct-Sowing Techniques
1. Briefly review optimal environmental considerations for seed germination
a) Soil moisture should be 65–80% of field capacity
b) Degree of secondary cultivation: Describe here, talk about differences between needs
of small vs. large seeds
c) Soil temperature: For warm-season crops, surface soil temperature should exceed
60º in the top 6 inches for majority of daylight hours
d) Depth of planting: General rule is to plant seeds twice as deep as the seeds are long.
Refer to seed packets or seed catalogs as reference
Instructor’s Demonstration 1 Outline Unit 1.4 | Part 1 – 177
Transplanting & Direct Seeding
2. Demonstrate and discuss the pros/cons of the various direct-sowing techniques
a) Drills/sowing into furrows by hand
b) Push seeder: Demonstrate multiple types, if available
c) Broadcast sowing
3. Irrigation
a) Objective: For small-seeded crops (e.g., lettuce, salad mix, carrots), maintain even
soil moisture until seed germination, when the oscillation between wet and dry can
be stretched gradually. Larger-seeded crops (e.g. peas, squash, seed potatoes) can
tolerate more of a wet-dry swing from the time they are planted; overwatering can
lead to rot.
b) Techniques and frequency used
i. Micro sprinklers
ii. Overhead sprinklers
iii. Dripline
iv. Discuss flow rates of each system in regards to frequency
4. Thinning established stand
a) Stage of development: Discuss when to thin
b) Density: See Appendix 1, Field-Scale Transplanting Guide
5. Questions and answers
Part 1 – 178 | Unit 1.4 Instructor’s Demonstration 1 Outline
Transplanting & Direct Seeding
Demonstration 1: Garden-Scale Transplanting &
Direct Sowing
step-by-step instructions for the students
A. Assess Plant, Soil, and Environmental Conditions Prior to Sowing or Transplanting
1. Seedling development
a) Shoot development
i. Second set of true leaves (cell format)
ii. Filling out allotted space and second set of true leaves established (flat format)
b) Root development
i. Root knit (cell format)
ii. Filling out allotted space (flat format)
2. Seedling pre-treatments
a) Soil/mix moisture
i. Field capacity (cell format)
ii. 75%–80% of field capacity (flat format)
b) Hardened-off
i. 3–21 day range (minimum of 3 days with 24 hours at field conditions)
ii. Hardening-off period should increase in duration with increased differential between
field and greenhouse conditions
3. Field or garden soil conditions
a) Soil moisture
i. 75–80% of field capacity
b) Degree of secondary cultivation
i. Extensive secondary cultivation for small-seeded, direct-sown crops and transplants
with small, weak, or inefficient root systems (e.g., carrots)
ii. Slightly less secondary tillage for large, vigorous, and resilient transplants (e.g.,
tomatoes, peppers)
4. Optimal environmental conditions favorable to successful transplanting from flat format
a) Low light levels
b) Low temperature
c) Calm winds
d) High relative humidity
e) Late afternoon and early evening
Note that you will seldom have all of these conditions in place; see information in
lecture outline for ways to compensate for less-than-ideal transplanting conditions
B. Transplanting
1. Gather necessary tools and materials
a) Seedlings at transplant maturity
b) Hand trowel and hand fork
c) Watering wand
d) Dibble or other transplant marker
Students’ Step-by-Step Instructions, Demonstration 1 Unit 1.4 | Part 1 – 179
Transplanting & Direct Seeding
e) String jig
f ) Measuring tape
g) Ross and hose
h) Micro-sprinklers
i) String and stakes
j) Seed
k) Push seeders (if available)
2. Plant spacing considerations: Consider how the following factors influence crop spacing
a) Irrigation and cultivation considerations
i. Rows should be straight and between-row crop spacing should be large enough to
accommodate drip irrigation line and cultivation tools
b) Root and shoot size
i. How large is the root system and vegetative portion of the plant at maturity?
c) Stem length and stem number in cut flowers
i. By increasing crop density in certain cut flowers, flower stem lengths may be
increased.
d) See Appendix 2, Common Transplant Spacings; Common Seeding Rates and Thinning
Distances, for recommendations
3. How to plant
a) Know the crop being planted
i. Review the crop culture information on the back of the seed package, in seed
catalogues, online, or in books on crop culture
b) Plant selection criteria (seedling vigor): Select for vigor
c) Plant handling
i. Crops grown in a flat format should be handled carefully by the rootball, attempting
to disturb the root system as little as possible during the transplanting process. Crops
grown in a flat format should only be transplanted during the late afternoon/early
evening or on cloudy days.
ii. Crops grown in a cell tray format may be planted throughout the day and with less
concern for disturbance of the root system during planting
d) Depth of planting
i. Most crops should be planted to the depth of the cotyledons (see Appendix 4,
Seedlings at Transplant Maturity, Planting Depth)
ii. Crops in the Solanaceae family (tomatoes, peppers, eggplants, etc.) and Brassicaceae
family (broccoli, cabbage, cauliflower, etc.) are adventitious rooters and may be
buried to the bottom of the first set of true leaves
4. Watering in
a) Seedlings should be immediately irrigated following transplanting
b) Bring the root zone of the crop to saturation (all pore spaces filled) using drip irrigation,
overhead sprinklers, micro sprinkler, or basal soaking with a watering wand or rose
5. Documenting
a) Transcribe the information on the horticultural label (including the transplanting date)
to a bed-end stake and the garden record log book (see Appendix 8)
6. Follow-up
a) Determine the type of irrigation to be used and set up any necessary irrigation
equipment at this time
Part 1 – 180 | Unit 1.4 Students’ Step-by-Step Instructions, Demonstration 1
Transplanting & Direct Seeding
b) Return remaining seedlings to the propagation area. Refill flats with propagation mix
and water thoroughly
c) Over the following approximately 2–5 days, monitor soil moisture in the root zone of the
recently transplanted crop. Irrigate once the soil in the root zone has reached 50–60%
of field capacity; at the depth of the root ball (2–4” deep) the soil should be right on the
edge of not “balling up” when squeezed. Note that it is better to water too early than to
stress new transplants by underwatering.
d) Periodic, light overhead irrigation will raise the relative humidity around the seedlings,
reduce the rate of evapotransporation, and help minimize transplant shock
e) Observe the growth and development of the roots and shoots of the seedlings, noting
the following: Rates of growth, changes in color, and damage due to predation
f ) Replace seedlings lost to predation. Use remay or other floating row cover to protect
seedlings from insect damage, as appropriate
C. Direct Sowing
1. Consider the optimal environmental conditions for seed germination in terms of:
a) Soil moisture
i. 75%–80% of field capacity
b) Degree of secondary cultivation
i. Extensive secondary cultivation is necessary for small-seeded direct-sown crops and
transplants with small, weak, or inefficient root systems
c) Soil temperature
i. Compare the existing soil temperatures with the optimal germination temperatures
found on the back of the seed package, in Knott’s Handbook for Vegetable Growers,
or in Appendix 2, Seed Viability Chart, of Unit 1.3, Propagating Crops from Seed, and
Greenhouse Management
2. Direct-sowing techniques
a) Sowing into furrows with hands
i. Open furrow with fingers or hand tool to a depth of approximately 2 times the
diameter of the seed to be sown
ii. Sow seed at 2–3 times the density desired at maturity (seedlings are later thinned to
desired spacing when the first set of true leaves have developed)
iii. Cover seed by pinching furrow together
iv. Gently tamp soil with head of rake to assure soil-to-seed contact
b) Sowing into furrows with push seeder
i. Consult the seed plate chart for use of push seeder
ii. Test seeder output on hard, flat surface to confirm desired seed rate/spacing
iii. Periodically check to assure seed output and seed supply in hopper
c) Broadcast sowing
i. Broadcast evenly over surface of soil
ii. Cover lightly with a mixture of 50% garden soil and 50% mature compost
3. Irrigating seed beds
a) Using Ross, oscillator, or mist/micro-sprinklers, maintain surface soil moisture with light,
frequent applications of water each time 50%–100% of the surface of the soil has dried
and discolored (see Appendix 6, Garden-Scale Seed Bed Irrigation)
4. Thinning direct-sown crops
a) Thin directly seeded crops to desired spacing, if necessary, once the first set of true
leaves has developed (see crop-spacing chart in Appendix 2 and in seed packages and
catalogues)
Students’ Step-by-Step Instructions, Demonstration 1 Unit 1.4 | Part 1 – 181
Transplanting & Direct Seeding
Part 1 – 182 | Unit 1.4
Transplanting & Direct Seeding
Demonstration 2: Field-Scale Transplanting &
Tractor-Mounted Seeding
for the instructor
INSTRUCTOR OVERVIEW PREPARATION AND MATERIALS
• Bed shaper/marker
This field demonstration outline • Tractor-mounted seeder
introduces the tractor-mounted • Push seeder
equipment and skills used to • Plate planter
transplant and direct seed crops. • Tractor-mounted transplanting equipment
It first covers the sequence of • Hand trowels
techniques and equipment used • Irrigation equipment: Drip and sprinkler
to prepare the soil for both • Record sheets for recording crops sown, and planted (see
transplanting and direct seeding. The
outline then introduces the range Appendices 7 and 8)
of equipment and techniques used • Labels for marking bed
to transplant and direct seed crops, • Shovels for single row plantings
followed by irrigation techniques.
GROUND PREPARATION
This demonstration requires access to an area of ground
that has received primary and secondary tillage, pre-irri-
gation, and weed cultivation. These techniques should be
included in the demonstration if not covered previously in
Unit 1.2, Garden and Field Tillage and Cultivation.
PREPARATION TIME
1 hour
DEMONSTRATION TIME
1 hour
Instructor’s Demonstration 2 Outline Unit 1.4 | Part 1 – 183
Transplanting & Direct Seeding
DEMONSTRATION OUTLINE
A. Review and Discuss Tools and Sequence Used to Prepare Ground
1. Review field soil conditions prior to tillage
a) Soil moisture range: 50%–60% of field capacity (see Appendix 5 in this unit, and
Unit 1.5, Irrigation—Principles and Practices, for discussion of field capacity)
2. Review steps involved in incorporation of cover crop residue through primary tillage
a) Mowing (flail or rotary)
b) Apply compost prior to residue incorporation, if necessary
c) Incorporate cover crop residue with spader or off-set wheel disc (see Unit
3. Establishment of seedbed through secondary tillage techniques
a) Rototill or disc field to improve surface uniformity following residue breakdown
4. Review steps involved in bed formation
a) Form beds with lister bar and shovels or rolling cultivator
b) Shape bed with bed shaper
c) Pre-irrigate to germinate weed seed; if using drip tape, pre-irrigate one week in
advance
d) Cultivate unplanted beds with sweeps, knives, or rolling cultivator to minimize weed
pressure and exhaust seed bank
e) Ensure good tilth: Important for roots of transplants to have access to water held in
soil pores; large clods don’t hold water
f) Plant beds with seeder, transplanter, or by hand
B. Demonstrate Bed Shaper/Seeder for Direct-Sown Crops
1. Review attachment of implement(s)
2. Demonstrate adjustment of bed shaper height
3. Demonstrate adjustment of seeder shovels’ height for seeding various crops
4. Demonstrate using markers on bed shaper to pull scratch lines for guiding straight
planting
5. Review examples of crops that are directly sown and why
C. Demonstrate Implements Used to Prepare Beds for Single-Line Plantings
1. Review attachment and adjustment of implement(s) used
2. Review examples of single-line crops
D. Review Planting Plan
1. Prepare planting map: Calculate how many feet of which crop will be planted (and
where), and have map ready for planting crew
2. Prepare list of plants to pick up from hardening-off area
E. Review Preparation for Transplanting
1. Transplant preparations: Irrigation and hardening off (see Unit 1.5, and discussion of
hardening off in this unit)
2. Ensure that transplants are ready: Knit together root plug, hardened off for one week,
firm stems, roots that are not wrapped
3. Planting considerations to minimize transplant shock
a) Plug trays should be saturated (dripping wet) prior to planting
b) Soil should be pre-irrigated
Part 1– 184 | Unit 1.4 Instructor’s Demonstration 2 Outline
Transplanting & Direct Seeding
c) Plant in cool of the day, or going into cool; e.g., in Central Valley, plant late
afternoon
d) Leave trays in shade if not planting immediately
e) Reschedule planting if extremely hot or windy
f) Have irrigation ready to turn on as soon as planting is done and before plants stress;
note that for sprinkler irrigation, planting block is equal to irrigation block
F. Review Hand Transplanting Techniques
1. Review of transplanted crops
a) Single line crops (tomatoes, peppers, eggplant, squash, melons, cucumbers)
b) Double line crops (brassicas, lettuce, celery, onions, leeks)
2. Handling and placement
a) To remove plants from plug trays, grasp stem firmly or drop tray on flat ground to
loosen plugs
b) Work in teams: one person drops plant in furrow, one person plants
c) Drop and plant one line at a time (i.e., don’t try and cover both lines of a raised bed)
d) Pay attention to designated spacing (i.e., 8”, 12”, etc.) and stay in scratch line so
plants don’t later get cultivated out during mechanical cultivation
e) Don’t leave plugs on soil surface for longer than 3–5 minutes
f) Planting depth: Cover plug entirely (Note: Sometimes, plants are placed on their
side if stems are leggy, e.g., tomatoes, sunflowers; or plant up to cotyledons, e.g.,
broccoli)
g) Avoid planting plug above air pockets
G. Demonstrate the Use of Mechanical Transplanter
1. Review attachment of implement(s)
2. Demonstrate adjustment of transplanter
3. Transplant preparations: Review irrigation and hardening off
4. Demonstrate handling and placement of transplants
5. Review examples of crops that are mechanically transplanted and why
6. Demonstrate adjustment of transplanter
H. Review Irrigation Techniques Used Immediately Following Transplanting and Direct Seeding
1. Drip irrigation
2. Sprinkler irrigation: Irrigation pipe is ready to hook up, pump is tested, etc.
3. Note that if block is mixed between direct sown and transplanted crops, direct sow
first so that water can be turned on as soon as transplants are in the ground
I. Demonstrate Clean Up
1. Wash out plug trays and sun-sterilize
J. Review Record Keeping
1. Record information on bed-end stakes (cultivar, planting date)
2. Record information in field logs (see Appendices 9 and 10)
Instructor’s Demonstration 2 Outline Unit 1.4 | Part 1 – 185
Transplanting & Direct Seeding
Assessment Questions
1) List three physical environmental conditions favorable for successful transplanting of flat-grown
seedlings.
2) What is the optimal range of soil moisture for transplanting or direct seeding of crops?
3) Describe how the size, root nature, and vigor of transplants and the size of seeds influence the
degree of secondary cultivation needed.
4) List two characteristics of seedlings at transplanting maturity.
5) List two necessary steps in preparing seedlings for transplanting.
Part 1 – 186 | Unit 1.4 Assessment Questions
Transplanting & Direct Seeding
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